On May 8, 2020, at 1:41 AM, Martin Ivanov <marto1980@gmail.com> wrote:

Hello,
Thank you for your replies. I think another version of MPICH may not work as I am following a tutorial (https://www2.mmm.ucar.edu/wrf/OnLineTutorial/compilation_tutorial.php) that requires specific library versions.
My /etc/hosts file contains only these two lines:

"
::1 localhost localhost.my.domain
127.0.0.1 localhost localhost.my.domain
"

uname -n returns an empty string as I have not set a hostname. I guess I do not need this because I need to run MPICH only on this machine, that is on localhost? uname -a gives the following output:

Thing is, though, your initial post showed ssh being used as launcher. So in that case you would definitely need a hostname so you can resolve back to yourself (your shell prompt was a big clue, by the way). Setting a hostname and making it an alias of localhost in /etc/hosts would probably do wonders no matter the underlying launch.

The -info output is pretty much the same as I see on FreeBSD.

If you run a hello world with a sleep in it to allow you to react, what does “ps x” show?